Deheubarth

Deheubarth was a Welsh kingdom that existed from 920 to 1197, with Dinefwr serving as its capital. It was united in 920 by Hywel Dda out of the territories of Seisyllwg and Dyfed, which had come into his possession. Hywel Dda created a new base at Dinefwr, the new capital of his kingdom, but Dinefwr was frequently overrun by enemies, including by Gwynedd in 1018, Morgannwg in 1023, and again by Gwynedd in 1041 and 1043. Following the death of Henry I of England in 1136, Gruffydd ap Rhys formed an alliance with Gwynedd for the purpose of a revolt against Norman incursions from England, defeating the English at Crug Mawr that same year; however, Gwynedd took Ceredigion for itself. In 1197, Rhys ap Gruffydd divided the kingdom among his sons, and it became a part of the Principality of Wales.